U.S. patent application number 11/421942 was filed with the patent office on 2006-12-07 for electronic device and method of manufacturing the same.
This patent application is currently assigned to SHINKO ELECTRIC INDUSTRIES CO., LTD.. Invention is credited to Takashi Otsuka.
Application Number | 20060273461 11/421942 |
Document ID | / |
Family ID | 37026966 |
Filed Date | 2006-12-07 |
United States Patent
Application |
20060273461 |
Kind Code |
A1 |
Otsuka; Takashi |
December 7, 2006 |
ELECTRONIC DEVICE AND METHOD OF MANUFACTURING THE SAME
Abstract
An electronic device includes a substrate 23 on which foot
patterns 24A, 24B and a solder resist 25 are provided such that the
foot patterns 24A, 24B are exposed from opening portions 27A, 27B
in the solder resist 25, packaging parts 20A, 20B mounted on the
substrate 23 by solder 26, and a sealing resin 29 formed on the
substrate 23 to seal the packaging parts 20A, 20B, wherein a part
(running-on portions 26A, 26B) of the solder 26 is constructed to
run on an upper surface of the solder resist 25 under the packaging
parts 20A, 20B.
Inventors: |
Otsuka; Takashi;
(Nagano-shi, Nagano, JP) |
Correspondence
Address: |
RANKIN, HILL, PORTER & CLARK LLP
4080 ERIE STREET
WILLOUGHBY
OH
44094-7836
US
|
Assignee: |
SHINKO ELECTRIC INDUSTRIES CO.,
LTD.
80, Oshimada-machi
Nagano-shi, Nagano
JP
|
Family ID: |
37026966 |
Appl. No.: |
11/421942 |
Filed: |
June 2, 2006 |
Current U.S.
Class: |
257/754 ;
257/686; 257/777; 29/832; 29/855 |
Current CPC
Class: |
H01L 2924/19105
20130101; H05K 3/284 20130101; Y10T 29/4913 20150115; H05K
2201/10977 20130101; Y02P 70/611 20151101; H05K 2203/1316 20130101;
H05K 2201/10734 20130101; H01L 2224/73204 20130101; H05K 2201/10636
20130101; Y02P 70/50 20151101; H05K 2201/10727 20130101; H01L
2224/05568 20130101; Y10T 29/49171 20150115; H05K 2201/2036
20130101; H01L 2224/16225 20130101; Y02P 70/613 20151101; H05K
2201/0989 20130101; H01L 2924/00014 20130101; H05K 3/305 20130101;
H01L 2224/05573 20130101; H05K 3/3442 20130101; H05K 2201/099
20130101; H01L 2224/0554 20130101; H05K 3/3452 20130101; H01L
2924/00014 20130101; H01L 2224/05599 20130101; H01L 2924/00014
20130101; H01L 2224/0555 20130101; H01L 2924/00014 20130101; H01L
2224/0556 20130101 |
Class at
Publication: |
257/754 ;
257/686; 257/777; 029/855; 029/832 |
International
Class: |
H01L 23/02 20060101
H01L023/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2005 |
JP |
2005-164387 |
Claims
1. An electronic device, comprising: a substrate on a surface of
which electrode patterns and a solder resist are provided such that
the electrode patterns are exposed from opening portions formed in
the solder resist; a packaging part mounted on the substrate, the
packaging part having packaging part electrodes connected to the
electrode patterns by solder; and a sealing resin formed on the
substrate to seal the packaging part, wherein a part of the solder
runs on an upper surface of the solder resist.
2. An electronic device according to claim 1, wherein, when the
substrate is viewed from a top, the solder resist has overlapping
portions that are overlapped with areas in which the packaging part
electrodes and the electrode patterns oppose to each other.
3. An electronic device according to claim 1, wherein the solder
resist is not provided in an area in which the packaging part and
the substrate oppose to each other.
4. An electronic device, comprising: a substrate on a surface of
which electrode patterns and a solder resist are provided such that
the electrode patterns are exposed from opening portions formed in
the solder resist; a packaging part mounted on the substrate, the
packaging part having packaging part electrodes connected to the
electrode patterns by solder; and a sealing resin formed on the
substrate to seal the packaging part, wherein a buried member is
provided into the electrode patterns respectively in a state that
it is buried in the solder.
5. An electronic device according to claim 4, wherein the buried
member is formed of the solder resist.
6. An electronic device according to claim 4, wherein, when the
substrate is viewed from a top, the buried member is provided to
areas in which the packaging part electrodes and the electrode
patterns oppose to each other.
7. A method of manufacturing an electronic device, comprising:
steps of applying solder to electrode patterns on a substrate on a
surface of which the electrode patterns and a solder resist are
provided such that the electrode patterns are exposed from opening
portions formed in the solder resist; mounting packaging part
electrodes, which are provided to a packaging part, on the
electrode patterns by using the solder; and forming a sealing
resin, which seals the packaging parts, on the substrate, wherein,
before the mounting step is executed, a thermosetting adhesive
having an activation power necessary for soldering is provided to a
position corresponding to a mounting position of the substrate, on
which the packaging part is mounted.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an electronic device and a
method of manufacturing the same. More particularly, the present
disclosure relates to an electronic device having such a structure
that a packaging part is mounted on a substrate by using solder,
and a method of manufacturing the same.
RELATED ART
[0002] In recent years, the demand for miniaturization of the
electronic device is increasing. Accordingly, in order to mount the
packaging device provided in the electronic device on the
substrate, a necessity to use the surface mounting and the
flip-chip mounting is increased (see JP-A-2005-109187, for
example).
[0003] An example of the surface mounting will be explained with
reference to FIG. 18 to FIG. 23 hereunder. FIG. 18 shows an
electronic device as a first related-art example. FIG. 19 shows a
substrate 3 used in the electronic device as the first related-art
example. Foot patterns 4A, 4B onto which packaging parts 1A, 1B are
soldered respectively are formed on a surface of the substrate 3.
Also, various wiring patterns (not shown) as well as to the foot
patterns 4A, 4B are formed on the surface of the substrate 3. A
solder resist 5, 5A, 5B is formed on the surface of the substrate 3
to protect the wiring patterns.
[0004] The solder resist 5, 5A, 5B is a resin having an insulating
performance and, as shown in FIG.2, opening portions 7A, 7B are
formed in positions opposing to the foot patterns 4A, 4B.
Therefore, the foot patterns 4A, 4B are exposed from the solder
resist 5 in positions in which the opening portions 7A, 7B are
formed.
[0005] The packaging parts 1A, 1B are surface-mounted on the foot
patterns 4A, 4B, which are exposed from the opening portions 7A, 7B
in the solder resist 5, with solder 6. More particularly, a
packaging part electrode 2A is provided to both side portions
respectively because the packaging part 1A is a ceramic chip part.
Also, the packaging part 1B is an electronic element such as an
oscillator, or the like, and packaging part electrodes 2B are
formed on a lower surface of the packaging part 1B. Then, when
these packaging parts are mounted, the solder paste is applied
previously to the foot patterns 4A, 4B, and then the packaging
parts 1A, 1B are mounted on the substrate 3 such that respective
electrodes 2A, 2B are positioned on the foot patterns 4A, 4B to
which the solder paste is applied. Then, the packaging parts 1A, 1B
are surface-mounted on the substrate 3 with solder 6 by executing
the reflow process under this condition.
[0006] An electronic device shown in FIG. 21 has the almost same
structure as the electronic device shown in FIG. 18. However, the
electronic device shown in FIG. 18 is constructed in such a manner
that areas of the opening portions 7A, 7B formed in the solder
resist 5 are smaller than areas of the foot patterns 4A, 4B
respectively and that outer peripheral portions of the foot
patterns 4A, 4B are covered with the solder resist 5. In contrast,
the electronic device shown in FIG. 21 is constructed such that the
areas of the opening portions 8A, 8B formed in the solder resist 5
are set larger than the areas of the foot patterns 4A, 4B
respectively and thus overall areas of the foot patterns 4A, 4B are
exposed from the solder resist 5 (see FIG. 22).
[0007] Meanwhile, as shown in FIG. 18 and FIG. 21, many electronic
devices in the related art are constructed such that the packaging
parts 1A, 1B are mounted on the substrate 3 in their exposed state,
i.e., in their uncovered state. However, since other people can
easily know how the packaging parts 1A, 1B and the wiring patterns
are arranged and constructed, these uncovered packaging structures
have the problem in terms of the know-how protection.
[0008] As the means for preventing this problem, as shown in FIG.
20 and FIG. 23, it may be considered that the packaging parts (only
the packaging parts 1A is illustrated in FIG. 20 and FIG. 23) are
sealed with a sealing resin 9. In electronic devices 10A, 10B
constructed in this manner, the sealing resin 9 formed of an opaque
resin makes it possible to prevent the arrangements and structures
of the packaging parts 1A, 1B and the wiring patterns from being
seen from the outside.
[0009] However, a minute clearance (indicated with an arrow Ah in
respective Figures) is formed between the packaging part 1A, when
mounted on the substrate 3, and the solder resist 5A, 5B. A
magnitude of this clearance .DELTA.h is varied due to a size of the
packaging part 1A, an applied amount of the solder 6, and the like,
and is given by almost 5 to 10 .mu.m, for example.
[0010] In this manner, when a minute clearance is formed between
the packaging part 1A and the solder resist 5A (substrate 3), the
sealing resin 9 cannot enter into such minute clearance when the
sealing resin 9 is provided. As a result, a void in which the
sealing resin 9 is not provided is generated between the packaging
part 1A and the solder resist 5A.
[0011] In the case where the void is generated in the sealing resin
9, when a heating process is carried out in mounting the electronic
devices 10A, 10B and the solder 6 is melted, the periphery of the
solder 6 is sealed with the sealing resin 9. Therefore, it is
possible that the melted solder 6 enters into the clearance and
thus the short-circuit is generated between the packaging part
electrodes 2A. Also, there is a possibility that an air in the
clearance is expanded by the heating and thus cracks are generated
in the sealing resin 9.
SUMMARY
[0012] The disclosure below describes an electronic device capable
of preventing not only generation of a short-circuit between
electrode patterns during heating but also generation of cracks in
a sealing resin by increasing an isolation distance between a
packaging part and a substrate, and a method of manufacturing the
same.
[0013] An example implementation of the invention is described
below.
[0014] An electronic device, comprises:
[0015] a substrate on a surface of which electrode patterns and a
solder resist are provided such that the electrode patterns are
exposed from opening portions formed in the solder resist;
[0016] a packaging part mounted on the substrate, the packaging
part having packaging part electrodes connected to the electrode
patterns by solder; and
[0017] a sealing resin formed on the substrate to seal the
packaging part;
[0018] wherein a part of the solder runs on an upper surface of the
solder resist.
[0019] In the above-mentioned structure, since a part of the solder
runs on an upper surface of the solder resist, an isolation
distance between the packaging part and the substrate can be set
large. Therefore, the sealing resin can be injected surely into
spaces between the packaging part and the substrate.
[0020] Also, in the electronic device, when the substrate is viewed
from a top, the solder resist may have overlapping portions that
are overlapped with areas in which the packaging part electrodes
and the electrode patterns oppose to each other.
[0021] In the above-mentioned structure, the overlapping portions
that are overlapped with areas where the packaging part electrodes
and the electrode patterns oppose to each other are provided to the
solder resist. Therefore, a part of the solder can be caused easily
to run on the upper surface of the solder resist (overlapping
portions).
[0022] Also, in the electronic device, the solder resist may not be
provided in an area in which the packaging part and the substrate
oppose to each other.
[0023] In the above-mentioned structure, the packaging part opposes
directly to the substrate and the solder resist is not present
between them. Therefore, a height of the packaging part from the
substrate can be set further large, and thus the sealing resin can
be injected more surely into the spaces between the packaging part
and the substrate.
[0024] Also, an electronic device, comprises:
[0025] a substrate on a surface of which electrode patterns and a
solder resist are provided such that the electrode patterns are
exposed from opening portions formed in the solder resist;
[0026] a packaging part mounted on the substrate, the packaging
part having packaging part electrodes connected to the electrode
patterns by solder; and
[0027] a sealing resin formed on the substrate to seal the
packaging part;
[0028] packaging part electrode wherein a buried member is provided
into the electrode patterns respectively in a state that it is
buried in the solder.
[0029] In the above-mentioned structure, since the buried member
buried in the solder is provided into the electrode patterns
respectively, the buried member is buried in the inside of the
solder when the solder is applied to the electrode patterns.
Therefore, a height of the solder is increased higher than a height
obtained when the buried member is not provided. As a result, an
isolation distance between the packaging part and the substrate can
be set large and thus the sealing resin can be injected without
fail into the spaces between the packaging part and the
substrate.
[0030] Also, in the electronic device, the buried member is formed
of the solder resist.
[0031] In the above-mentioned structure, the buried member is
formed of the solder resist. Therefore, the buried member can be
formed at the same time when the solder resist is formed.
[0032] Also, in the electronic device, when the substrate is viewed
from a top, the buried member is provided to areas in which the
packaging part electrodes and the electrode patterns oppose to each
other.
[0033] In the above-mentioned structure, the buried member is
provided to the areas where the packaging part electrodes oppose to
the electrode patterns. Therefore, the buried member can be
provided without fail to the inside of the solder.
[0034] Also, a method of manufacturing an electronic device,
comprises: steps of
[0035] applying solder to electrode patterns on a substrate on a
surface of which the electrode patterns and a solder resist are
provided such that the electrode patterns are exposed from opening
portions formed in the solder resist;
[0036] mounting packaging part electrodes, which are provided to a
packaging part, on the electrode patterns by using the solder;
and
[0037] forming a sealing resin, which seals the packaging part, on
the substrate;
[0038] wherein, before the mounting step is executed, a
thermosetting adhesive having an activation power necessary for
soldering is provided to a position corresponding to a mounting
position of the substrate, on which the packaging part is
mounted.
[0039] In the above-mentioned structure, since a thermosetting
adhesive having an activation power necessary for the soldering is
provided before the mounting step is executed, the packaging part
can be secured to the substrate by using this adhesive in the
mounting step. Also, since the solder is activated by the activator
contained in the adhesive when the packaging part is soldered to
the wiring patterns in the mounting step, the soldering can be
executed without fail. In addition, since the adhesive is present
between the packaging part and the substrate in the sealing step,
no clearance is generated between the packaging part and the
substrate when the sealing resin is formed.
[0040] Various implementations may include one or more the
following advantages. For example, since an isolation distance
between the packaging part and the substrate can be set large, the
sealing resin can be introduced surely into the spaces between the
packaging part and the substrate. Thus, even when the sealing resin
is formed, no clearance is generated between the packaging part and
the substrate. Therefore, it can be prevented that a short-circuit
between the packaging parts patterns via the solder entered into
the clearance is generated, and also it can be prevented that an
air in the clearance is expanded by heating to exert a bad
influence upon the sealing resin, and the like. As a result,
reliability of the electronic device can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a side view showing a state before a sealing resin
is provided to an electronic device as a first embodiment of the
present invention.
[0042] FIG. 2 is a plan view of a substrate constituting the
electronic device as the first embodiment of the present
invention.
[0043] FIG. 3 is a sectional view of the electronic device as the
first embodiment of the present invention.
[0044] FIG. 4 is a plan view showing a variation of a substrate
constituting the electronic device as the first embodiment of the
present invention.
[0045] FIG. 5 is a side view showing a state before a sealing resin
is provided to an electronic device as a second embodiment of the
present invention.
[0046] FIG. 6 is a plan view of a substrate constituting the
electronic device as the second embodiment of the present
invention.
[0047] FIG. 7 is a sectional view of the electronic device as the
second embodiment of the present invention.
[0048] FIG. 8 is a sectional view of an electronic device as a
third embodiment of the present invention.
[0049] FIG. 9 is a view (#1) explaining a method of manufacturing
the electronic device as the third embodiment.
[0050] FIG. 10 is a view (#2) explaining the method of
manufacturing the electronic device as the third embodiment.
[0051] FIG. 11 is a view (#3) explaining the method of
manufacturing the electronic device as the third embodiment.
[0052] FIG. 12 is a sectional view of an electronic device as a
fourth embodiment of the present invention.
[0053] FIG. 13 is a view (#1) explaining a method of manufacturing
the electronic device as the fourth embodiment.
[0054] FIG. 14 is a view (#2) explaining the method of
manufacturing the electronic device as the fourth embodiment.
[0055] FIG. 15 is a view (#3) explaining the method of
manufacturing the electronic device as the fourth embodiment.
[0056] FIG. 16 is a view (#1) explaining a variation of a method of
manufacturing the electronic device as the fourth embodiment.
[0057] FIG. 17 is a view (#2) explaining the variation of the
method of manufacturing the electronic device as the fourth
embodiment.
[0058] FIG. 18 is a side view showing a state before a sealing
resin is provided to an electronic device as a first related-art
example.
[0059] FIG. 19 is a plan view of a substrate constituting the
electronic device as the first related-art example.
[0060] FIG. 20 is a sectional view of the electronic device as the
first related-art example.
[0061] FIG. 21 is a side view showing a state before a sealing
resin is provided to an electronic device as a second related-art
example.
[0062] FIG. 22 is a plan view of a substrate constituting the
electronic device as the second related-art example.
[0063] FIG. 23 is a sectional view of the electronic device as the
second related-art example.
DETAILED DESCRIPTION
[0064] Next, the best mode for carrying out the present invention
will be explained with reference to the drawings hereinafter.
[0065] FIG. 1 to FIG. 3 are views explaining an electronic device
30A as a first embodiment of the present invention. FIG. 1 is a
side view showing a state before a sealing resin 29 is provided to
the electronic device 30A, FIG. 2 is a plan view of a substrate 23
constituting the electronic device 30A, and FIG. 3 is a
longitudinal sectional view of the electronic device 30A.
[0066] The electronic device 30A comprises packaging parts 20A,
20B, the substrate 23, the sealing resin 29, and the like. The
packaging part 20A is a ceramic chip parts such as a resistor, a
capacitor, or the like, for example, and packaging part electrodes
22A are formed on both sides of the packaging part 20A. Also, the
packaging part 20B is an electronic element such as a SAW filter,
an oscillator, or the like, for example, and packaging part
electrodes 22B are formed on a lower surface of the packaging part
20B.
[0067] The substrate 23 is a printed-wiring board, for example, and
foot patterns 24A, 24B are formed on a surface of the substrate 23.
The foot patterns 24A are the electrode patterns used to mount the
packaging part 20A, and the foot patterns 24B are the electrode
patterns used to mount the packaging parts 20. Also, various wiring
patterns 31 as well as the foot patterns 24A, 24B are formed on a
surface of the substrate 23. In the present embodiment, the wiring
patterns 31 are provided to positions that oppose to the packaging
part 20B.
[0068] A solder resist 25 is formed on the surface of the substrate
23 to protect the wiring patterns 31. The solder resist 25 is
provided to the surface of the substrate 23 such that, when the
solder is applied, solder 26 is not deposited on conductors (e.g.,
the wiring patterns 31) other than the foot patterns 24A, 24B. The
solder resist 25 is formed relatively easily in a desired shape by
the screen printing, or the like.
[0069] As shown in FIG. 2, opening portions 27A, 27B are formed in
the solder resist 25. The opening portions 27A, 27B are formed to
correspond to forming positions of the foot patterns 24A, 24B
formed on the substrate 23. More particularly, the opening portion
27A is formed to correspond to the foot patterns 24A on which the
packaging part 20A is mounted, and also the opening portions 27B
are formed to correspond to the foot patterns 24B on which the
packaging part 20B is mounted.
[0070] Also, a length L1 of the opening portion 27A in the arrow X
direction in FIG. 2 is set shorter than a length L2 of the
packaging part 20A (in FIG. 2, its outer shape is indicated by a
chain double-dashed line) in the arrow X direction in a mounted
state (L2>L1). Also, two opening portions 27B are formed on the
right and left sides in FIG. 2 to put a lower resist 25A of the
packaging part 20B between them. In this case, a length L3 between
a left end portion and a right end portion containing two opening
portions 27B in FIG. 2 is set shorter than a length L4 of the
packaging part 20B (in FIG. 2, its outer shape is indicated by a
chain double-dashed line) in the arrow X direction in a mounted
state (L4>L3).
[0071] Now, a relationship between the foot patterns 24A, 24B and
the solder resist 25 will be mentioned hereunder. The present
embodiment is constructed such that a part of the foot patterns
24A, 24B is covered with the solder resist 25. Suppose hereunder
that a portion of the solder resist 25 for covering a part of the
foot patterns 24A is referred to as an overlapping portion 32A and
a portion of the solder resist 25 for covering a part of the foot
patterns 24B is referred to as an overlapping portion 32B.
[0072] Respective overlapping portions 32A, 32B are provided on
outer positions of the foot patterns 24A, 24B. In the present
embodiment, the overlapping portion 32A (32B) is provided to extend
in the arrow X direction only in FIG. 2, and a width dimension of
the overlapping portion 32A is given by a width indicated by an
arrow X1 (X2) in FIG. 2.
[0073] The overlapping portions 32A, 32B are constructed such that
they are positioned in areas of the packaging parts 20A, 20B in
their mounted state (areas indicated by a chain double-dashed line
in FIG. 2). In other words, the overlapping portions 32A, 32B are
constructed to oppose to the packaging parts 20A, 20B when the
packaging parts 20A, 20B are mounted on the substrate 23.
[0074] Also, in the present embodiment, the solder resist 25
located between a pair of foot patterns 24A, 24A is not provided.
Therefore, as shown in FIG. 1, the packaging part 20A is faced
directly to the substrate 23 before it is sealed with the sealing
resin 29.
[0075] In contrast to this, the wiring patterns 31 are provided
between the left and right foot patterns 24B on the side where the
packaging part 20B is provided. In order to protect the wiring
patterns 31, the lower resist 25A is formed between the left and
right foot patterns 24B on the side where the packaging part 20B is
provided.
[0076] The solder paste is applied onto the foot patterns 24A, 24B
to mount the packaging parts 20A, 20B on the substrate 23. At this
time, the solder paste is applied onto not only upper surfaces of
the foot patterns 24A, 24B but also upper surfaces of the
overlapping portions 32A, 32B.
[0077] Then, the packaging parts 20A, 20B are aligned with the
substrate 23 such that the electrodes 22A, 22B are positioned on
the foot patterns 24A, 24B onto which the solder paste is applied,
and then the packaging parts 20A, 20B are fitted onto the substrate
23. In this state, the packaging parts 20A, 20B are temporarily
fitted to the substrate 23 by the solder paste.
[0078] Then, the substrate 23 to which the packaging parts 20A, 20B
are temporarily fitted is put into the reflow furnace, and then the
reflow process is carried out. As a result, organic components in
the solder paste are evaporated and the solder is melted. Then, the
packaging part electrodes 22A, 22B of the packaging parts 20A, 20B
are soldered to the foot patterns 24A, 24B with the solder 26 after
the melted solder 26 is cooled/solidified.
[0079] FIG. 1 shows a state that the packaging parts 20A, 20B are
secured to the foot patterns 24A, 24B with the solder 26. Here, the
solder 26 in the present embodiment is mentioned hereunder. In the
present embodiment, a part of the solder 26 is formed to run on the
upper portion of the solder resist 25 (portion of the solder 26
formed to run on the upper portion of the solder resist 25 is
referred to as running-on portions 26A, 26B respectively
hereinafter).
[0080] In this manner, a part of the solder 26 is formed to run on
the upper portion of the solder resist 25. Therefore, the packaging
part 20A is positioned higher than the upper portion of the solder
resist 25 by a thickness of the running-on portion 26A (indicated
by an arrow .DELTA.H1 in FIG. 1) in its mounted state, and also the
packaging part 20B is positioned higher than the upper portion of
the solder resist 25 by a thickness of the running-on portion 26B
(indicated by an arrow .DELTA.H2 in FIG. 1).
[0081] The thicknesses (.DELTA.H1, .DELTA.H2) of the running-on
portions 26A, 26B can be adjusted by areas of the overlapping
portions 32A, 32B overlapped on the foot patterns 24A, 24B (in
other words, exposed areas of the foot patterns 24A, 24B), an
applied amount of the solder 26, and the like.
[0082] Also, in order to form the running-on portion 26A, 26B
(solder 26) on the solder resist 25 that has essentially a low
affinity for the solder, it is important that in fact outwardly
extruded portions of the foot patterns 24A, 24B should be
positioned on as inner the side as possible of the packaging areas
(indicated by a chain double-dashed line in FIG. 2) of the
packaging parts 20A, 20B such that they are not positioned on the
outer side from the packaging areas of the packaging parts 20A,
20B. Also, it is important that, when the substrate 23 onto which
the packaging parts 20A, 20B are mounted is viewed from the top,
the overlapping portions 32A, 32B should be provided in areas that
are overlapped with the areas where the packaging part electrodes
22A, 22B are opposed to the foot patterns 24A, 24B.
[0083] With the above configuration, the running-on portion 26A,
26B can be prevented from leaking out from outer peripheries of the
packaging parts 20A, 20B to the outer side. Accordingly, the
running-on portion 26A, 26B can be held between the packaging parts
20A, 20B and the substrate 23 (the foot patterns 24A, 24B, the
overlapping portions 32A, 32B)
[0084] As a result, the packaging parts 20A, 20B can be isolated
more largely from the substrate 23 than the related art (see FIG.
18 to FIG. 23). More concretely, on the packaging side of the
packaging part 20A, the solder resist 25 under the packaging
position of the packaging part 20A is not provided. Thus, an
isolation distance between the substrate 23 and the packaging part
20A is given by a distance indicated by an arrow Z1 in FIG. 1.
[0085] Also, on the packaging side of the packaging part 20B, the
lower resist 25A is formed between the packaging part 20B and the
substrate 23 because of the presence of the wiring patterns 31.
Thus, an isolation distance between a surface of the lower resist
25A and the lower surface of the packaging part 20B is given by a
distance indicated by an arrow Z2 in FIG. 1.
[0086] Both isolation distances Z1, Z2 can be increased large
rather than the related art (.DELTA.H indicated in FIG. 20 and FIG.
23). Concretely, the isolation distances Z1, Z2, although varied
due to the exposed area of the foot pattern 24A, an applied amount
of the solder 26, etc., can be set to 20 .mu.m to 30 .mu.m, for
example.
[0087] As shown in FIG. 3, the sealing resin 29 is formed to seal
the packaging parts 20A, 20B provided onto the substrate 23. The
sealing resin 29 is made of an epoxy resin, and is formed by using
the transfer molding method, for example.
[0088] In the present embodiment, since the isolation distances Z1,
Z2 between the packaging parts 20A, 20B and the substrate 23 can be
set large as described above, the sealing resin 29 can be
introduced without fail into spaces (33A, 33B) between the
packaging parts 20A, 20B and the substrate 23. In particular, on
the packaging side of the packaging part 20A, the sealing resin 29
can be introduced more surely because the solder resist 25 is not
present between the packaging part 20A and the substrate 23.
[0089] In this way, in the electronic device 30A according to the
present embodiment, since the sealing resin 29 is introduced into
the spaces between the packaging parts 20A, 20B and the substrate
23, a clearance is never generated between the packaging parts 20A,
20B and the substrate 23. Therefore, even when the heating is
applied upon mounting the electronic device 30A, and the like, a
short-circuit between the foot patterns 24A, 24B via the solder 26
is never generated, and also the sealing resin 29 is never badly
influenced by the expansion of the air in the clearance. As a
result, reliability of the electronic device 30A can be
improved.
[0090] FIG. 4 shows the substrate 23 provided to an electronic
device as a variation of the first embodiment of the present
invention. The first embodiment shown in FIG. 2 is constructed such
that the overlapping portions 32A, 32B are provided to extend in
the arrow X direction in FIG. 2 only. In contrast, this variation
is characterized in that the overlapping portions 32A, 32B are
provided to extend not only in the arrow X direction in FIG. 4 but
also in the arrow Y direction in FIG. 4.
[0091] In an example shown in FIG. 4, width dimensions of extended
portions of the overlapping portions 32A, 32B in the arrow Y
direction are set to widths indicated by arrows Y1, Y2
respectively. In this variation, the forming positions of the
overlapping portions 32A, 32B are not limited to one side of the
foot patterns 24A, 24B, and they may be formed on two sides.
[0092] Next, a second embodiment of the present invention will be
explained hereunder.
[0093] FIG. 5 to FIG. 7 are views explaining an electronic device
30B as a second embodiment the present invention. In FIG. 5 to FIG.
7, the same reference symbols are affixed to the same configuration
as the electronic device 30A according to the first embodiment
shown in FIG. 1 to FIG. 3, and their explanation will be omitted
herein.
[0094] The above electronic device 30A according to the first
embodiment is characterized in that respective heights of the
packaging parts 20A, 20B from the substrate 23 are increased since
a part of the solder 26 is formed to run on the upper portion of
the solder resist 25 to constitute the running-on portions 26A,
26B, and thus the sealing resin 29 can be introduced without fail
into the spaces between the packaging parts 20A, 20B and the
substrate 23.
[0095] In contrast, the electronic device 30B according to the
present embodiment is characterized in that a buried member 35 is
provided to the foot patterns 24A, 24B respectively. This buried
member 35 is formed collectively upon forming the solder resist 25,
and thus the buried member 35 is formed of the same material as the
solder resist 25.
[0096] Also, as shown in FIG. 6, the forming position of the buried
member 35 is selected in almost center portions of the foot
patterns 24A, 24B. As described above, the solder resist 25 can be
formed easily by the screen printing, or the like, and printing
(application) positions can be selected flexibly.
[0097] Therefore, the buried member 35 can be formed easily in the
almost center portions of the foot patterns 24A, 24B. Also, since
the buried member 35 is formed simultaneously with the solder
resist 25, simplification of the manufacturing steps of the
electronic device 30B can be achieved.
[0098] Also, in the present embodiment, the overlapping portions
32A, 32B are not provided on the foot patterns 24A, 24B. As shown
in FIG. 5 and FIG. 6, the foot patterns 24A, 24B are constructed to
be exposed totally from opening portions 28A, 28B respectively.
[0099] Next, a process of mounting the packaging parts 20A, 20B on
the substrate 23, which has the foot patterns 24A, 24B in which the
buried member 35 is provided respectively, will be explained
hereunder. In mounting the packaging parts 20A, 20B, first the
solder paste is applied to the foot patterns 24A, 24B in which the
buried member 35 is provided. At this time, the solder paste is
applied to cover the buried member 35.
[0100] Then, the packaging parts 20A, 20B are aligned with the
substrate 23 such that respective electrodes 22A, 22B are
positioned on the foot patterns 24A, 24B, and then the packaging
parts 20A, 20B are mounted/fitted onto the substrate 23. In this
state, the packaging parts 20A, 20B are temporarily fitted to the
substrate 23 by the solder paste.
[0101] Then, the substrate 23 is put into the reflow furnace, and
then the reflow process is carried out. As a result, organic
components in the solder paste are evaporated and the solder is
melted. Then, the packaging part electrodes 22A, 22B of the
packaging parts 20A, 20B are soldered to the foot patterns 24A, 24B
with the solder 26 after the melted solder 26 is
cooled/solidified.
[0102] Since the buried member 35 is formed in the almost center
portions of the foot patterns 24A, 24B respectively, the melted
solder 26 will assume the shape close to a sphere because of a
surface tension when the solder 26 is melted. Therefore, even
though the buried member 35 is formed of the solder resist, such
buried member 35 is positioned in the inside of the solder 26.
Then, the buried member 35 is buried in the solder 26 after the
solder 26 is cooled in this state.
[0103] In this manner, since the buried member 35 is buried in the
solder 26, a height of the solder 26 is increased higher than that
of the solder 26 obtained when the buried member 35 is not
provided. That is, a height of the solder 26 is increased by a
height that corresponds to a volume of the buried member 35.
Therefore, in the electronic device 30B according to the present
embodiment, an isolation distance between the packaging parts 20A,
20B and the substrate 23 can be set large, and thus the sealing
resin 29 can be introduced surely into the spaces between the
packaging parts 20A, 20B and the substrate 23.
[0104] As a result, in the electronic device 30B according to the
present embodiment, like the electronic device 30A according to the
first embodiment, the clearance is never generated between the
packaging parts 20A, 20B and the substrate 23. Therefore, even when
the heating is applied upon mounting the electronic device 30B, and
the like, a short-circuit between the foot patterns 24A, 24B via
the solder 26 is never generated, and also the sealing resin 29 is
never badly affected by the expansion of the air in the clearance.
As a result, reliability of the electronic device 30B can be
improved.
[0105] Next, a third embodiment of the present invention will be
explained hereunder.
[0106] FIG. 8 is a sectional view of an electronic device 30C as a
third embodiment of the present invention. FIG. 9 to FIG. 11 are
views explaining a method of manufacturing the electronic device
30C. In FIG. 9 to FIG. 11 used to explain the present embodiment,
the same reference symbols are affixed to the same configuration as
the electronic device 30A according to the first embodiment shown
in FIG. 1 to FIG. 3, and their explanation will be omitted
herein.
[0107] The electronic device 30C according to the present
embodiment is characterized in that an underfill resin 36 is
provided between the packaging parts 20A, 20B and the substrate 23.
This underfill resin 36 is provided in isolation spaces between the
lower resists 25A, which are provided between the neighboring foot
patterns 24A and the neighboring foot patterns 24B respectively,
and the packaging parts 20A, 20B. For this reason, the spaces
between the packaging parts 20A, 20B and the substrate 23 are
filled with the underfill resin 36 in a mounted state, and thus no
clearance is formed in the spaces.
[0108] Therefore, even when the heating is applied upon mounting
the electronic device 30C, and the like, a short-circuit between
the foot patterns 24A, 24B via the solder 26 is never generated,
and also the sealing resin 29 is never badly affected by the
expansion of the air in the clearance. As a result, reliability of
the electronic device 30C can be improved.
[0109] Next, the method of manufacturing the electronic device 30C
will be explained hereunder. In order to manufacture the electronic
device 30C, the substrate 23 on which the foot patterns 24A, 24B
are formed previously in predetermined patterns respectively and
also the opening portions 27A, 27B are formed in predetermined
patterns in the solder resist 25 is prepared. In the present
embodiment, the foot patterns 24A, 24B are formed such that they
are exposed totally from the opening portions 27A, 27B formed in
the solder resist 25.
[0110] First, a process of applying a solder paste 37 to the
substrate 23 is executed (solder applying step). In this solder
applying step, the solder paste 37 is printed on the foot patterns
24A, 24B exposed from the opening portions 27A, 27B by using the
screen printing method. FIG. 9 shows a state that the solder paste
37 is provided on the foot patterns 24A, 24B by using the screen
printing method.
[0111] Then, the packaging parts 20A, 20B are provided onto the
foot patterns 24A, 24B on which the solder paste 37 is provided.
More particularly, the packaging part electrodes 22A of the
packaging part 20A are aligned with the foot patterns 24A, the
packaging part electrodes 22B of the packaging part 20B are aligned
with the foot patterns 24B, and the packaging part electrodes 22A,
22B are pushed against the solder paste 37. As a result, the
packaging parts 20A, 20B are temporarily fitted onto the substrate
23 by an adhesive strength of the solder paste 37.
[0112] Then, the substrate 23 onto which the packaging parts 20A,
20B are temporarily fitted is put into the reflow furnace and is
heated. Thus, the organic components in the solder paste 37 are
vaporized and the solder is melted. Then, the packaging part
electrodes 22A, 22B are secured to the foot patterns 24A, 24B with
the solder 26 by executing the cooling (mounting step). FIG. 10
shows a state that the packaging part electrodes 22A, 22B are
mounted onto substrate 23 with the solder 26 after the mounting
step is finished. In this state, a clearance is formed between the
packaging part electrodes 22A, 22B and the lower resists 25A
respectively.
[0113] In this case, the packaging parts 20A, 20B are not sealed
with the sealing resin 29 at a time of heating by using the reflow
process. Therefore, the melted solder 26 can be freely moved, but
such melted solder 26 never flows out from the upper surfaces of
the foot patterns 24A, 24B by a surface tension even when the
solder 26 is expanded. As a result, a short-circuit is never
generated between the neighboring the foot patterns 24A and the
neighboring the foot patterns 24B respectively.
[0114] Then, the underfill resin 36 is filled in the spaces formed
between the packaging part electrodes 22A, 22B and the substrate 23
(lower resists 25A) respectively (underfill filling step). This
process of filling the underfill resin 36 can be executed by using
the dispensers, for example. FIG. 11 shows the substrate 23 after
the underfill filling step is finished.
[0115] Then, the sealing resin 29 for sealing the packaging part
electrodes 22A, 22B is formed on the substrate 23 on which the
underfill resin 36 is filled between the packaging part electrodes
22A, 22B and the lower resists 25A respectively (sealing step).
This sealing resin 29 is an epoxy resin and is formed by using the
transfer molding method, for example. At this time, no clearance is
formed in the sealing resin 29 because the underfill resin 36 is
filled between the packaging part electrodes 22A, 22B and the lower
resists 25A respectively, as described above. The electronic device
30C shown in FIG. 8 can be manufactured via a series of above
steps.
[0116] Next, a fourth embodiment of the present invention will be
explained hereunder.
[0117] FIG. 12 is a sectional view of an electronic device 30D as a
fourth embodiment of the present invention. FIG. 13 to FIG. 15 are
views explaining a method of manufacturing the electronic device
30D. In FIG. 13 to FIG. 15 used to explaining the present
embodiment, the same reference symbols are affixed to the same
configuration as the electronic device 30A according to the first
embodiment shown in FIG. 1 to FIG. 3, and their explanation will be
omitted herein.
[0118] The electronic device 30D according to the present
embodiment is characterized in that a fluxfill resin 38 is filled
in the spaces between the packaging parts 20A, 20B and the
substrate 23. This fluxfill resin 38 is a thermosetting adhesive
having an activation power necessary for the soldering. More
particularly, the fluxfill resin 38 can fulfill a function as the
adhesive when it is cured by the heating, and also can fulfill a
function as the activator to remove an oxidation film on a surface
of the solder and enhance fluidity of the melted solder when it is
heated.
[0119] The fluxfill resin 38 is provided in isolation spaces
between the packaging parts 20A, 20B and the lower resists 25A
provided between the neighboring foot patterns 24A and the
neighboring foot patterns 24B respectively. Therefore, the spaces
between the packaging parts 20A, 20B and the substrate 23 are
filled with the fluxfill resin 38 in the mounted state, and thus
the clearance is never formed therein.
[0120] Therefore, even when the heating is applied in mounting the
electronic device 30D according to the present embodiment, and the
like, a short-circuit between the foot patterns 24A, 24B via the
solder 26 is never generated, and also the sealing resin 29 is
never harmfully influenced by the expansion of the air in the
clearance. As a result, reliability of the electronic device 30D
can be improved.
[0121] Next, the method of manufacturing the electronic device 30D
will be explained hereunder. In order to manufacture the electronic
device 30D, the substrate 23 on which the foot patterns 24A, 24B
are formed previously in predetermined patterns respectively and
also the opening portions 27A, 27B are formed in predetermined
patterns in the solder resist 25 is prepared. In the present
embodiment, the foot patterns 24A, 24B are formed such that they
are exposed totally from the opening portions 27A, 27B formed in
the solder resist 25.
[0122] First, a process of applying the solder paste 37 to the
substrate 23 is executed (solder applying step). In this solder
applying step, the solder paste 37 is printed on the foot patterns
24A, 24B exposed from the opening portions 27A, 27B by using the
screen printing method. Also, in the present embodiment, the
substrate 23 on which the solder paste 37 is applied onto the foot
patterns 24A, 24B is put into the reflow furnace and the heating
process is executed, and thus the organic components in the solder
paste 37 are vaporized and the solder 26 is formed on the foot
patterns 24A, 24B (solder applying step). FIG. 13 shows the
substrate 23 on which the solder 26 is formed on the foot patterns
24A, 24B.
[0123] Then, the fluxfill resin 38 is provided the position that
lies under the packaging part 20A when mounted (between the
neighboring foot patterns 24A) and the position that lies under the
packaging part 20B when mounted (between the neighboring foot
patterns 24B) (fluxfill resin providing step). In the present
embodiment, a film-like fluxfill resin is used as the fluxfill
resin 38. Also, in the present embodiment, the film-like fluxfill
resin 38 is arranged in the predetermined positions.
[0124] FIG. 14 shows a state that the film-like fluxfill resin 38
is arranged on the substrate 23. As shown in FIG. 14, the fluxfill
resin 38 is arranged to cover upper areas of the solder 26 formed
on the foot patterns 24A, 24B.
[0125] In this case, the fluxfill resin 38 is not limited to the
film-like fluxfill resin. The liquid fluxfill resin 38 may be
coated on the predetermined positions by a potting, or the
like.
[0126] Then, the packaging parts 20A, 20B are arranged on the
substrate 23 on which the fluxfill resin 38 is provided. More
particularly, the packaging part electrodes 22A of the packaging
parts 20A are aligned with the foot patterns 24A, the packaging
part electrodes 22B of the packaging parts 20B are aligned with the
foot patterns 24B, and the packaging part electrodes 22A, 22B are
pushed against the fluxfill resin 38.
[0127] As a result, the packaging parts 20A, 20B are temporarily
fitted onto the substrate 23 by an adhesive strength of the
fluxfill resin 38. Also, the packaging part electrodes 22A, 22B of
the packaging parts 20A, 20B come into contact with the solder 26.
FIG. 15 shows a state that the packaging parts 20A, 20B are
temporarily fitted onto the substrate 23.
[0128] Then, the substrate 23 onto which the packaging parts 20A,
20B are temporarily fitted is put into the reflow furnace and is
heated. Accordingly, the solder 26 is melted again. Then, the
packaging part electrodes 22A, 22B are secured to the foot patterns
24A, 24B with the solder 26 by executing the cooling (mounting
step).
[0129] At this time, the fluxfill resin 38 is thermally cured by
the heating and the packaging parts 20A, 20B are adhered to the
substrate 23. The packaging parts 20A, 20B are secured to the
substrate 23 by an adhesive strength of the fluxfill resin 38 in
addition to a jointing strength of the solder 26. For this reason,
the packaging parts 20A, 20B are secured without fail to the
substrate 23 and thus mechanical reliability of the electronic
device 30D can be enhanced.
[0130] Also, since the fluxfill resin 38 contains the activator, an
oxidation film formed on the surface of the solder 26 is removed
and also the fluidity of the melted solder 26 can be increased when
the solder 26 is melted by the heating. Hence, the packaging part
electrodes 22A, 22B and the foot patterns 24A, 24B are connected
more surely by the solder 26, and also reliability of the
electronic device 30D can be enhanced in an electric aspect.
[0131] In the present embodiment, the packaging parts 20A, 20B are
not sealed by the sealing resin 29. Therefore, a short-circuit is
never generated between the neighboring the foot patterns 24A and
the neighboring the foot patterns 24B respectively at a time of
heating executed by the reflow process.
[0132] Then, the sealing resin 29 for sealing the packaging part
electrodes 22A, 22B is formed on the substrate 23 on which the
fluxfill resin 38 is interposed between the packaging part
electrodes 22A, 22B and the lower resists 25A respectively (sealing
step). This sealing resin 29 is an epoxy resin and is formed by
using the transfer molding method, for example. At this time, no
clearance is formed in the sealing resin 29 since the fluxfill
resin 38 is filled between the packaging part electrodes 22A, 22B
and the lower resists 25A respectively, as described above. The
electronic device 30D shown in FIG. 12 can be manufactured via a
series of above steps.
[0133] FIG. 16 and FIG. 17 are views explaining a variation of a
method of manufacturing the electronic device 30D as the fourth
embodiment. In the method of manufacturing the electronic device
30D, the solder paste 37 is printed on the foot patterns 24A, 24B
on the substrate 23, and then the fluxfill resin 38 and the
packaging parts 20A, 20B are provided after the solder paste 37 is
changed into the solder 26 by the heating.
[0134] In contrast, in the present variation, as shown in FIG. 16,
the solder paste 37 is printed on the foot patterns 24A, 24B by the
screen printing, and then the fluxfill resin 38 is coated on the
upper surfaces of the lower resists 25A. In this case, the printing
of the solder paste 37 on the substrate 23 and the coating of the
fluxfill resin 38 onto the lower resists 25A can be reversed in
order.
[0135] After the solder paste 37 and the fluxfill resin 38 are
provided to the substrate 23 as described above, the packaging
parts 20A, 20B are aligned with the substrate 23 and then mounted
thereon, like the above embodiments, as shown in FIG. 17.
Therefore, the packaging parts 20A, 20B are temporarily fitted to
the substrate 23 by the solder paste 37 and the adhesive agent in
the fluxfill resin 38.
[0136] Then, the substrate 23 to which the packaging parts 20A, 20B
are temporarily fitted is put into the reflow furnace, and then the
heating process is carried out. Accordingly, the packaging part
electrodes 22A, 22B are soldered onto the foot patterns 24A, 24B
with the solder 26, and also the packaging parts 20A, 20B are
adhered/secured to the substrate 23 by the fluxfill resin 38. As a
result, the electronic device 30D shown in FIG. 12 can be
manufactured.
* * * * *